Abrading tool and holder therefor

ABSTRACT

A removable abrading tool in the form of a base plate and an integral abrasive member. The base plate has, in one embodiment, a plurality of tabs extending therefrom and the integral abrasive member, for example, is a mesh-like metalic sheet. The abrading tool is releasably secured to a tool holder having integral means for deforming the tabs whereby the abrading tool is securely held in place when in use. The abrading tool may be easily removed by applying a force thereto that tends to straighten out the tabs. Means are provided for mounting the combined holder and abrading tool, for example in the three-jaw chuck of a tool such as a motor driven drill, or the like.

United States Patent Weissman ABRADING TOOL AND HOLDER THEREFOR Inventor: Bernard Weissman, 225 E. 48th St.,

New York. N IYT 10017 FOREIGN PATENTS OR APPLICATIONS Great Britain 51/358 Primary Examiner0thell M. Simpson Attorney, Agent. or FirmFriedman & Goodman [57] ABSTRACT A removable abrading tool in the form of a base plate and an integral abrasive member. The base plate has. in one embodiment. a plurality of tabs extending therefrom and the integral abrasive member. for example, is a mesh-like metalic sheet. The abrading tool is releasably secured to a tool holder having integral means for deforming the tabs whereby the abrading tool is securely held in place when in use. The abrading tool may be easily removed by applying a force thereto that tends to straighten out the tabs. Means are provided for mounting the combined holder and abrading tool, for example in the three-jaw chuck of a tool such as a motor driven drill, or the like.

30 Claims, 13 Drawing Figures PATENTEDFEBI 9 3.864.884

SHEET 1 OF 4 PATENIEUFEHI I 1925 sum 2 OF 4 FIGQ FIG. IO

PATENTED FEB] I I975 SHEET 3 [IF 4 PATENTEDFEBI H915 I 3.864.884

SHEET 4 [IF 4 w FIG. l3

1 ABRADING TOOL AND HOLDER THEREFOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to material removal devices and more particularly to an improved abrading tool and a holder therefor.

2. Description of the Prior Art Power driven abrading tools that are useful in metal working and wood working and which are adapted to be coupled to thechuck of a power drill 'or the like, are well known in the art. Generally speaking the prior art devices are comprised of a shank that is adapted to be retained by the jaws of the drill chuck and a disc secured to the shank. An abrasive sheet is frequently secured to the disc or alternatively,a wire brush may be secured to the disc. After some extended use and when the abrading member is no longer useful it is necessary to discard entire tool including the disc and the shank which have not necessarily deteriorated. It will be evident then that some unnecessary waste is involved with the prior art devices that render them excessively costly. Another drawback to the prior art devices, is that, when it is desired to use different abrasive media, it is necessary to replace the entire unit including the shank and the disc that supports the abrasive portion. Thus it will be appreciated that this too adds to the cost of the prior art and also represents some inconvenience and loss of time since the drill chuck must be opened, usually with a special key in order to release the prior art devices.

SUMMARY OF THE INVENTION The present invention provides an economical, combination abrading tool and tool holder therefor that permits rapid assembly and simplified interchangeability of the abrasive portion. In one embodiment, the present invention provides an 'interchangeableabrading tool that comprises a base plate and an abrasive member that is rigidly secured to the rim of the base plate. At least one tab and preferrably a plurality of tabs extend from the surface of the base plate that is opposite the abrading member. The tabs are readily deformable. The holder for theabrading tool includes two plates that are relatively movable with respect to each other. The tabs of the base plate of the abrading tool are initially received in slots formed in one of the two plates of the tool holder. The other plate of the tool holder includes projections positioned adjacent the tabs.

When the two tool holder plates are moved relative to each other the tabs are bent by the projections and positioned against the rear surface of the tool holder retainer plate so that the abrading tool is securely held. When it is necessary to either replace or interchange the abrading tool with another tool of different abrasiveness, opposed pulling forces are applied to the base plate of the abrading tool and to the tool holder which causes the tabs to straighten out so that they may be removed from the slots. A headed shaft is mounted in the first or retainer plate of the tool holder and extends through an axial extension of a hub formed in the second or support plate of the toolholder. The headed shaft is suitably secured to the hub extension of the second plate so that the retainer and support plates of the tool holder become an integral unit, but one which is still capable of relative movement between the components thereof.

As will be evident from the description that follows, the abrading tool is very simply mounted on the tool holder and the tool holder is very simply mounted in the jaws of a drill chuck, for example. The abrading tool may be very easily removed from the tool holder merely by pulling on it in order to return the tabs, from their bent or secured position, to a 'position that approximates their original condition. Thus the abrading tool may easily be changed or replaced without having to discard the tool holder therefor. It will therefore be very convenient for a machinist or a hobbyist to have a wide range of abrasive tools readily available that will satisfy virtually any finishing requirement.

Accordingly it is an object of the present invention to provide an improved abrading tool and tool holder therefor.

It is another object of the present invention to provide an improved abrading tool and tool holder therefor, as described above, that may be readily assembled and disassembled.

Another object of the present invention is to provide an abrading tool and tool holder therefor, as described above, wherein the abrading tool is removed merely by applying a pulling force.

A further object of the present invention is to provide an improved abrading tool and tool holder therefor, as described above, wherein the abrading tool is securely held in place by applying a twisting force so that the abrading tool and tool holder are angularly displaced relative to each other.

These and other objects, features and advantages of the invention will, in part, be pointed out with particularity, and will, in part,-become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawing, which forms an integral part thereof.

DESCRIPTION OF THE DRAWING In the various figures of the drawing like reference characters designate like parts. In the drawings:

FIG. 1 is perspective view of the improved abrading tool and holder therefor comprising the present invention;

FIG. 2 is a longitudinal, sectional elevational view taken along line 22 of FIG. 1;

FIG. 3 is a sectional, elevational view taken along line 33 of FIG. 2 illustrating the original condition and relative positions of certain of the components of the present invention;

FIG. 4 is a view similar to FIG. 3 illustrating the same components in a second secured position;

FIG. 5 is an elevational view illustrating the retainer plate comprising the present invention;

FIG. 6 is a sectional, elevation view taken along line 66 of FIG. 5:

FIG. 7 is an elevational view illustrating the support plate comprising the present inventions;

FIG. 8 is a sectional, elevational view taken along line 8-8 of FIG. 7;

FIG. 9 is an elevational view, partially broken away, illustrating the abrasive tool comprising the present invention;

FIG. 10 is a sectional elevational view taken along line 10-10 of FIG. 9;

FIG. 11 is an exploded, perspective view illustrating the three separate plates comprising the present invention;

FIG. 12 is an exploded perspective view, similar to FIG. 11 but illustrating the reverse side of the components shown in FIG. 11; and

FIG. 13 is a fragmentary, exploded, sectional view illustrading the abrasive tool comprising the present invention prior to the assembly thereof with the tool holder comprising the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring not to the drawing, and in particular FIG. 1, there is shown an improved, combination abrading tool and tool holder 20. As may best be seen in FIG. 2 the combination abrading tool and tool holder 20 is comprised of an abrading member 24, a retainer plate 26 for the abrading member 24, a support plate 28 for securing the abrading member 24 and coupling means 30 in the form of a headed shaft for coupling the retainer plate 26 and the support plate 28. The construction of each of the aforementioned components will be described in detail and then the assembly and mode operation thereof will be discussed.

Turning now to FIG. and FIG. 6, there is shown the retainer plate 26 which may be made of glass filled nylon, for example, which is comprised of a ring 32 and a central hub 34. A plurality of segments or spokes 36 extend generally radially between the rim 32 and the hub 34 so as to define a plurality of wedge-shaped openings 38. A slot 40 having a beveled edge 42 extends through each of the spokes 36. In addition the front surface of 44a of each spoke 36 is provided with three concentric grooves 46. Finally, there is provided a a counterbored opening 48 through the hub 34. As shown for example in FIG. 12, the reverse surface 44b of each spoke 36 is provided with a wedge-shaped recess 49 of which the radially extending sidewalls 49a define limiting means to be described hereinafter.

The support plate 28, which may also be made of glass filled nylon, for example, is shown in detail in FIG. 7 and FIG. 8. The support plate 28 is also comprised of a rim 50, a central hub 52 and three connecting segments or spokes 54. On the front surface 56 of the support plate 28, specifically within the area defined by each of the spokes 54, there is provided a projection 58, each of which includes a sloping cam surface 60. For purposes to be described hereinafter and by a comparison of FIG. 5 and FIG. 7 it will be seen that the projections 58, with their cam surfaces 60, are offset with respect to the slots 40. On the rear surface 62 of the support plate 28 there is provided an axial extension 64 having a longitudinal bore 66 therethrough and a transverse opening 68 extending through extension 64.

The abrasive member 24 comprising the present invention may best be seen in FIG. 9 and FIG. 10. The abrasive member 24 is comprised of a base plate 70 which is made of a deformable metal, such as an aluminum alloy for example. A plurality of tabs 72, equal in number to the slots 40 and the projections 58, extend away from the rear surface 74 of the base plate 70. In addition a plurality of openings 76 are formed through the base plate 70. The abrasive member 24 is further provided with a folded over rim 77 that defines an annular peripheral slot 78 for receiving an abrasive disc 80 which may be made of any suitable abrasive material, for example a perforated or mesh-like metallic plate. In the preferred embodiment of this invention as particularly shown in FIG. 10, the working surface 82 of the abrasive disc 80 is in a plane that is forward of the rim 77.

As shown in FIG. 2 and FIG. 13, the retainer plate 26 and the support plate 28 are coupled to each other by means of the shaft 30. The enlarged head portion 30a of the shaft 30 is received in the enlarged diameter of the counterbored hole 48 while the shank portion 30b of the shaft 30 is received in the smaller diameter portion of the counterbored hole 48. At assembly, the hole 68 of the support plate 28 is drilled through both walls of the hub extension 64 and a pin 84 is force fit through the extension and the shaft 30b. In this position the projections 58 on the surface 56 of the support plate 28 are located within the recesses 49 formed on the rear surface 44b of the retainer plate 24. The bores 48 and 66 in the retainer plate 26 and the support plate 28 respectively, and the diameters of the shaft 30 are dimensioned such that relative angular movements between the retainer plate 26 and the support plate 28 is permitted within the limits defined by the radially extending walls 49a of the recesses 49. Because the retainer plate 26 and the support plate 28 are made of low friction material there will be a minimum of resistance between the two components.

As shown in FIG. 13 the tabs 72 are in alignment with the slots 40. The same condition is illustrated in FIG. 2 and FIG. 3. More specifically, and as particularly shown in FIG. 3 the tabs 72 are adjacent the sloping surface 60 of each projection 58. When the retainer plate 26 and the support plate 28 are moved angularly relative to each other, the sloping surface 60 of each projection 58 will bear against its respective tab 72 and bend it upwardly against the rearward base wall of the recess 49. In this condition the three tabs 72 securely hold the abrasive member 24 to the retainer plate 26.

The shaft 30, as described hereinabove, adjustably couples the retainer plate 26 to the support plate 28. The shaft 30 may then be inserted into the chuck (not shown) of a conventional, motor driven drill (not shown). When the abrading tool is being used, the openings 76 in the abrasive member 24, the concentric grooves 46 in the retainer plate 26 and the aligned openings 38 and 55 in the retainer plate 26 and the support plate 28, respectively permit a free flow of the material being abraded in a direction away from the surface being worked on. When the abrasive member 24 is no longer serviceable or when it is necessary to replace the abrasive member 24 with another like member having a different degree of abrasiveness, all that is necessary is to provide a pulling force to the right, as shown by the arrows a in FIG. 2, to the abrasive member 24 in order to pull the tabs 72 out of the slot 40. An opposing force in the direction of the arrows b" is applied to the tool holder, as shown in FIG. 2. Because the material of the baseplate is readily deformable it will be relatively easy to return the tabs 72 to substantially their original condition by the application of the pulling force.

From the foregoing, it will be appreciated that a relatively inexpensive abrading tool and tool holder have been provided. The abrading tool may be easily inserted and will be positively retained by angularly displacing one of the two plates on which the abrading member is mounted. The abrading tool may be easily removed merely by applying a pulling force thereto.

There has been disclosed heretofor the best embodiment of the invention presently contemplated. However, it is to be understood that various changes and modifications may be thereto without departing from the spirit of the invention.

What is claimed is:

l. A motor driven holder for a tool having an abrasive surface and at least one deformable tab, said holder comprising:

a. a retainer plate adjacent which the tool is adapted to be mounted, said retainer plate having at least one slot through a portion thereof for receiving the tab of the tool;

b. a support plate including deforming means located adjacent the slot in said retainer plate for distorting the tab therein and thereby preventing removal of the tab from the slot when the tool is in use, the tool being removable from said retainer plate when not in use by the application of a force to the tool whereby the tab is restored to at least approximately the original condition thereof prior to being distorted so that the tab is movable through the slot; and

c. means for coupling said retainer plate to said support plate while permitting relative displacement therebetween whereby when one of said plated is moved said deforming means will bend the tab into a position that prevents removal of the tool during usage.

2. The holder according to claim 1 wherein there are a plurality of tabs on a surface of the tool that is remote from the abrasive surface with the tabs extending in a direction that is substantially perpendicular to the plane of the abrasive surface, said retaining plate including an equal number of slots through a wall that is in a plane substantially perpendicular to the direction of the tabs and said support plate includes an equal number of said deforming means.

3. The holder according to claim 2 wherein said deforming means comprises projections integral with said support plate, said projections being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.

4. The holder according to claim 2 wherein said deforming means comprises inclined surfaces integral with said support plate, said inclined surfaces being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.

5. The holder according to claim 2 wherein said retainer plate includes recesses in the surface thereof that is adjacent said support plate for receiving said deforming means, the walls of said recesses defining means for limiting the relative movement between said retainer plate and said support plate.

6. The holder according to claim 2 wherein said retainer plate and said support plate include contiguous openings therethrough that are in communication with the surface of the tool that is adjacent said retainer plate whereby material removed by the abrasive surface of the tool may flow through the openings in said retainer plate and said support plate.

7. The holder according to claim 6 wherein the surface of said retainer plate adjacent the tool includes a plurality of concentric grooves extending between the openings in said retainer plate.

8. The holder according to claim 2 wherein said retainer plate includes a counterbored hole therethrough 5 and said support plate includes a hub having an axial extension and a bore therethrough that is coaxial with the counterbored hole in said retainer plate, said coupling means comprising a shaft having an enlarged head portion positioned in the larger diameter of the counterbored hole in said retainer plate, the body of said shaft extending through the bore in said support plate, said coupling means further comprising means for rigidly securing said shaft to said hub extension, said shaft being adapted to be secured to the motor.

9. The holder according to claim 8 wherein the slots in said retainer plate are radially outward of the axis of the counterbored hole in said retainer plate and are radially oriented. I

10. The holder according to claim 2 wherein the slots in said retainer plate are beveled along the peripheral edge thereof adjacent the tool for facilitating insertion of the tabs.

11. An abrading tool adapted to be used with a motor driven holder having at least one tool retaining slot therein, said tool comprising:

a. a base plate having at least one deformable tab depending from one transverse surface thereof and adapted to be releaseably retained in the slot in the tool holder;

b. an abrasive member mounted on a transverse surface of said base plate opposite said tab surface; and

c. securing means for securing said abrasive member to said base plate, said securing means including an annular rim that is folded over and clamped against a periphery of said abrasive member.

12. The abrading tool according to claim 11 wherein there are a plurality of slots in the tool and at least as many of said tabs on said base plate as there are slots in the tool. I

13. The abrading tool according to claim 11 wherein said base plate is perforated.

14. The abrading tool according to claim 11 wherein the plane of said abrasive member is higher than said 15. The abrading'tool according to claim 11 wherein said abrasive member is made of a mesh-like metallic material.

16. A device of the type described, said device comprising, in combination:

a. a base plate having at least one deformable tab depending from a transverse surface thereof;

b. an abrasive member mounted on another transverse surface of said base plate that is opposed to said tab surface;

c. means for securing said abrasive member to said base plate;

d. a retainer plate adjacent which said base plate is mounted, said retainer plate having at least one slot through a portion thereof for receiving said tab of said base plate;

e. a support plate including deforming means located adjacent the slot in said retainer plate for distorting said tab therein thereby preventing removal of said tab from the slot when said abrasive member is in use, said abrasive member being removable from said retainer plate when not in use by the application of a force to said abrasive member whereby said tab is restored to at least approximately the original condition thereof prior to being distorted so that said tab is movable through the slot; and

f. means for coupling said retainer plate to said support plate while permitting relative displacement therebetween whereby when one of said plates is moved, said deforming means will bend said tab into a position that prevents removal of said abrasive member.

17. The device according to claim 16 wherein there are a plurality of tabs on a surface of the tool that is remote from the abrasive surface with the tabs extending in a direction that is substantially perpendicular to the plane of the abrasive surface, said retaining plate including an equal number of slots through a wall that is in a plane substantially perpendicular to the direction of the tabs and said support plate includes an equal number of said deforming means.

18. The device according to claim 16 wherein said deforming means comprises projections integral with said support plate, said projections being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.

19. The device according to claim 16 wherein said deforming means comprises inclined surfaces integral with said support plate said inclined surfaces being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.

20. The device according to claim 16 wherein said retainer plate includes recesses in the surface thereof that is adjacent said support plate for receiving said deforming means, the walls of said recesses defining means for limiting the relative movement between said retainer plate and said support plate.

21. The device according to claim 16 wherein said retainer plate and said support plate includes contiguous openings therethrough that are in communication with the surface of the tool that is adjacent said retainer plate whereby material removed by the abrasive surface of the tool may flow through the openings in said retainer plate and said support plate.

22. The device according to claim 21 wherein the surface of said retainer plate adjacent the tool includes a plurality of concentric grooves extending between the openings in said retainer plate.

23. The device according to claim 16 wherein said retainer plate includes a counterbored hole therethrough the said support plate includes a hub having an axial extension and a bore therethrough that is coaxial with the counterbored hole in said retainer plate, said coupling means comprising a shaft having an enlarged head portion positioned in the larger diameter of the counterbored hole in said retainer plate, the body of said shaft extending through the bore in said support plate, said coupling means further comprising means for rigidly securing said shaft to said hub extension, said shaft being adapted to be secured to the motor.

24. The device according to claim 2 wherein the slots in said retainer plate are radially outward of the axis of the counterbored hole in said retainer plate and are radically oriented.

25. The device according to claim 16 wherein the slots in said retainer plate are beveled along the peripheral edge thereof adjacent the tool for facilitating insertion of the tabs.

26. The device according to claim 16 wherein there are a plurality of slots in said retainer plate and at least as many of said tabs on said base plate as there are slots in said retainer plate.

27. The device according to claim 16 wherein said base plate is perforated.

28. The device according to claim 16 wherein said securing means comprises an annular rim on said base plate that is folded over and clamped against the periphery of said abrasive member.

29. The device according to claim 28 wherein the plane of said abrasive member is higher than said rim.

30. The device according to claim 16 wherein said abrasive member is made of a mesh-like metallic material. 

1. A motor driven holder for a tool having an abrasive surface and at least one deformable tab, said holder comprising: a. a retainer plate adjacent which the tool is adapted to be mounted, said retainer plate having at least one slot through a portion thereof for receiving the tab of the tool; b. a support plate including deforming means located adjacent the slot in said retainer plate for distorting the tab therein and thereby preventing removal of the tab from the slot when the tool is in use, the tool being removable from said retainer plate when not in use by the application of a force to the tool whereby the tab is restored to at least approximately the original condition thereof prior to being distorted so that the tab is movable through the slot; and c. means for coupling said retainer plate to said support plate while permitting relative displacement therebetween whereby when one of said plated is moved said deforming means will bend the tab into a position that prevents removal of the tool during usage.
 2. The holder accordIng to claim 1 wherein there are a plurality of tabs on a surface of the tool that is remote from the abrasive surface with the tabs extending in a direction that is substantially perpendicular to the plane of the abrasive surface, said retaining plate including an equal number of slots through a wall that is in a plane substantially perpendicular to the direction of the tabs and said support plate includes an equal number of said deforming means.
 3. The holder according to claim 2 wherein said deforming means comprises projections integral with said support plate, said projections being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.
 4. The holder according to claim 2 wherein said deforming means comprises inclined surfaces integral with said support plate, said inclined surfaces being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.
 5. The holder according to claim 2 wherein said retainer plate includes recesses in the surface thereof that is adjacent said support plate for receiving said deforming means, the walls of said recesses defining means for limiting the relative movement between said retainer plate and said support plate.
 6. The holder according to claim 2 wherein said retainer plate and said support plate include contiguous openings therethrough that are in communication with the surface of the tool that is adjacent said retainer plate whereby material removed by the abrasive surface of the tool may flow through the openings in said retainer plate and said support plate.
 7. The holder according to claim 6 wherein the surface of said retainer plate adjacent the tool includes a plurality of concentric grooves extending between the openings in said retainer plate.
 8. The holder according to claim 2 wherein said retainer plate includes a counterbored hole therethrough and said support plate includes a hub having an axial extension and a bore therethrough that is coaxial with the counterbored hole in said retainer plate, said coupling means comprising a shaft having an enlarged head portion positioned in the larger diameter of the counterbored hole in said retainer plate, the body of said shaft extending through the bore in said support plate, said coupling means further comprising means for rigidly securing said shaft to said hub extension, said shaft being adapted to be secured to the motor.
 9. The holder according to claim 8 wherein the slots in said retainer plate are radially outward of the axis of the counterbored hole in said retainer plate and are radially oriented.
 10. The holder according to claim 2 wherein the slots in said retainer plate are beveled along the peripheral edge thereof adjacent the tool for facilitating insertion of the tabs.
 11. An abrading tool adapted to be used with a motor driven holder having at least one tool retaining slot therein, said tool comprising: a. a base plate having at least one deformable tab depending from one transverse surface thereof and adapted to be releaseably retained in the slot in the tool holder; b. an abrasive member mounted on a transverse surface of said base plate opposite said tab surface; and c. securing means for securing said abrasive member to said base plate, said securing means including an annular rim that is folded over and clamped against a periphery of said abrasive member.
 12. The abrading tool according to claim 11 wherein there are a plurality of slots in the tool and at least as many of said tabs on said base plate as there are slots in the tool.
 13. The abrading tool according to claim 11 wherein said base plate is perforated.
 14. The abrading tool according to claim 11 wherein the plane of said abrasive member is higher than said rim.
 15. The abrading tool according to claim 11 wherein said abrasive member is made of a mesh-like metallic material.
 16. A device of the type described, said device compRising, in combination: a. a base plate having at least one deformable tab depending from a transverse surface thereof; b. an abrasive member mounted on another transverse surface of said base plate that is opposed to said tab surface; c. means for securing said abrasive member to said base plate; d. a retainer plate adjacent which said base plate is mounted, said retainer plate having at least one slot through a portion thereof for receiving said tab of said base plate; e. a support plate including deforming means located adjacent the slot in said retainer plate for distorting said tab therein thereby preventing removal of said tab from the slot when said abrasive member is in use, said abrasive member being removable from said retainer plate when not in use by the application of a force to said abrasive member whereby said tab is restored to at least approximately the original condition thereof prior to being distorted so that said tab is movable through the slot; and f. means for coupling said retainer plate to said support plate while permitting relative displacement therebetween whereby when one of said plates is moved, said deforming means will bend said tab into a position that prevents removal of said abrasive member.
 17. The device according to claim 16 wherein there are a plurality of tabs on a surface of the tool that is remote from the abrasive surface with the tabs extending in a direction that is substantially perpendicular to the plane of the abrasive surface, said retaining plate including an equal number of slots through a wall that is in a plane substantially perpendicular to the direction of the tabs and said support plate includes an equal number of said deforming means.
 18. The device according to claim 16 wherein said deforming means comprises projections integral with said support plate, said projections being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.
 19. The device according to claim 16 wherein said deforming means comprises inclined surfaces integral with said support plate said inclined surfaces being arranged to bear against the tabs when there is relative movement between said support plate and said retainer plate.
 20. The device according to claim 16 wherein said retainer plate includes recesses in the surface thereof that is adjacent said support plate for receiving said deforming means, the walls of said recesses defining means for limiting the relative movement between said retainer plate and said support plate.
 21. The device according to claim 16 wherein said retainer plate and said support plate includes contiguous openings therethrough that are in communication with the surface of the tool that is adjacent said retainer plate whereby material removed by the abrasive surface of the tool may flow through the openings in said retainer plate and said support plate.
 22. The device according to claim 21 wherein the surface of said retainer plate adjacent the tool includes a plurality of concentric grooves extending between the openings in said retainer plate.
 23. The device according to claim 16 wherein said retainer plate includes a counterbored hole therethrough the said support plate includes a hub having an axial extension and a bore therethrough that is coaxial with the counterbored hole in said retainer plate, said coupling means comprising a shaft having an enlarged head portion positioned in the larger diameter of the counterbored hole in said retainer plate, the body of said shaft extending through the bore in said support plate, said coupling means further comprising means for rigidly securing said shaft to said hub extension, said shaft being adapted to be secured to the motor.
 24. The device according to claim 2 wherein the slots in said retainer plate are radially outward of the axis of the counterbored hole in said retainer plate and are radically oriented.
 25. The device according to claim 16 whErein the slots in said retainer plate are beveled along the peripheral edge thereof adjacent the tool for facilitating insertion of the tabs.
 26. The device according to claim 16 wherein there are a plurality of slots in said retainer plate and at least as many of said tabs on said base plate as there are slots in said retainer plate.
 27. The device according to claim 16 wherein said base plate is perforated.
 28. The device according to claim 16 wherein said securing means comprises an annular rim on said base plate that is folded over and clamped against the periphery of said abrasive member.
 29. The device according to claim 28 wherein the plane of said abrasive member is higher than said rim.
 30. The device according to claim 16 wherein said abrasive member is made of a mesh-like metallic material. 